Pressurizable dilatometer system and apparatus

ABSTRACT

Dilatometer systems for measuring characteristics of material samples are disclosed. In one embodiment, a dilatometer system includes a reactor adapted to receive the test sample, a density trap in fluid communication with the reactor, a first fluid selectively filling the reactor and a portion of the density trap, and a second fluid selectively filling a portion of the density trap. The first fluid and the second fluid are immiscible with one another and selectively form an immiscible fluid boundary in the density trap. The dilatometer system further includes a heater that selectively heats the first fluid.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application62/303,411, filed Mar. 4, 2016.

TECHNICAL FIELD

Various configurations of the current invention relate generally to anapparatus, systems, and methods for measuring changes in volume. Moreparticularly, the apparatus, systems, and methods relate to using adilatometer for measuring changes in volume. Specifically, theapparatus, systems, and methods provide for a dilatometer that uses apair of at least two immiscible liquids.

BACKGROUND

Dilatometers are analytical instruments that measure the change involume of a substance due to thermal, physical or chemical processes.Generally, these instruments employ a variable temperature electricfurnace in which the test specimen is heated at a programmed rate to adesired elevated test temperature. Conventionally, the test specimen,which commonly is from about 10 to about 50 mm in length, is held withinsuch furnace between a flat surface on a stationary object and anopposing flat surface on a movable object, such as a ceramic pushrod,that extends outside the furnace. Temperature induced changes in thelength of the specimen are transmitted through the rod to a dilationsensor, which can be a mechanical, optical or electrical system foramplifying and measuring the change in position of the rod. Conventionalinstruments are useful for measuring specimen dilation within the rangeof from ambient temperature to the maximum temperature of the furnace,which commonly is about 1000 degrees Celsius and often is as high as1500 degrees Celsius or more.

The least complicated dilatometers in common use are those in which thepush rod is coupled to a dial gauge and the dilation of a specimen isread directly from that gauge. Such dial gauge dilatometers are simpleto use and inexpensive, but generally are suitable only for low tomoderately elevated temperature applications that do not demand highprecision. According, dilatometers with improved precision may bedesired.

SUMMARY

In one embodiment, a pressurizable dilatometer system may be used todetermine a glass transition temperature, as well as other parameters,of a test material. The dilatometer system includes a reactor to receivea test sample, a pump, a density trap, a first fluid line connectedbetween and placing the reactor and the density trap into fluidcommunication, a second fluid line connected between and placing thepump and the density trap into fluid communication, a first fluidadapted to fill the reactor, the first fluid line and a portion of thedensity trap. A second fluid fills a reservoir and/or other portions ofthe pump, the second fluid line and a portion of the density trap. Thefirst and second fluids form an immiscible fluid pair. In otherconfigurations, three or more fluids may be used to create two or moreimmiscible fluid boundaries. An immiscible fluid boundary is formedwhere the first and second pair of immiscible fluids meet in the densitytrap. In one use of the dilatometer system, the pump creates a pressurevalue on the first and second fluids forming the immiscible fluid pairwhich in turn creates a similar pressure on and the test sample. Amovement of the immiscible fluid boundary is used to determine a changein the system volume. In some embodiments, the first fluid is any liquidmetal or metal alloy and the second fluid is a power transferring fluid.For example, the first fluid may be Galinstan® or another liquid metalor metal alloy that is liquid over the range of temperatures ofinterest.

Another configuration is a pair of immiscible fluids in a pressurizabledilatometer system. The dilatometer system includes a reactor adapted toreceive a test sample. A working fluid that is a first fluid of animmiscible fluid pair of fluid is adapted to fill the reactor. Ahydraulic fluid that is a second fluid of an immiscible fluid pair is incontact with the first fluid to form an immiscible fluid boundary. Apump is adapted to pump the second fluid to create at least one pressurevalue on the second fluid, the first fluid, and the test sample. Aheater is adapted to heat the first fluid as well as the test sample inthe reactor over a range of temperature values. A movement of theimmiscible fluid boundary is used to calculate one or more parameters ofthe test sample including, for example, a glass transition temperature,T_(g), of the test sample. In some embodiments, the first fluid is aliquid metal or a liquid gallium eutectic alloy, including beingGalinstan.

Another configuration is a method of using two different fluids in adilatometer that form an immiscible fluid pair. The method begins byfilling a reactor containing a test sample as well a first fluid lineleading at least partially into a density trap with a first fluid. Asecond fluid is pumped through a second fluid line and at leastpartially into the density trap so that the first fluid and the secondfluid contact each other in the density trap forming an immiscible fluidinterface. A desired pressure is applied to the second fluid topressurize the second fluid, the first fluid, and the test sample. Thereactor and test sample are also optionally heated through a range oftemperatures. The glass transition temperature is found based, at leastin part, on the movement of the immiscible fluid interface in thedensity trap. In some configurations, the rate of movement of theimmiscible interface changes, indicating a rate of change of a specificvolume of the test sample, which indicates at what temperature the glasstransition temperature, T_(g), occurs. In some configurations, the firstfluid is Galinstan and the second fluid is a fluid that is immisciblewith the first fluid and generally incompressible at the workingpressures, such that the second fluid may transfer pressure to the firstfluid.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more preferred embodiments that illustrate the best mode(s) areset forth in the drawings and in the following description. The appendedclaims particularly and distinctly point out and set forth embodimentsaccording to the present disclosure.

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate various example methods and otherexample embodiments of various aspects of the disclosure. It will beappreciated that the illustrated element boundaries (e.g., boxes, groupsof boxes, or other shapes) in the figures represent one example of theboundaries. One of ordinary skill in the art will appreciate that insome examples, one element may be designed as multiple elements or thatmultiple elements may be designed as one element. In some examples, anelement shown as an internal component of another element may beimplemented as an external component and vice versa. Furthermore,elements may not be drawn to scale.

FIG. 1 illustrates an example embodiment of a volumetric dilatometersystem according to one or more embodiments.

FIG. 2 illustrates an example graph of specific volume vs. temperatureand where the glass transition temperature, T_(g), is found for anamorphous material and where the freezing temperature, T_(f), is foundfor a crystalline material.

FIG. 3 illustrates another example embodiment of a volumetricdilatometer system according to one or more embodiments.

FIG. 4 illustrates an example method of using a pair of immisciblefluids to find characteristics of material such as the glass transitiontemperature, T_(g), for example according to one or more embodiments.

FIG. 5 illustrates an example computer system that may aid in operatinga dilatometer system when finding characteristics of a test sampleaccording to one or more embodiments.

Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION

As used herein, “hydraulic fluid” refers to a fluid that is capable oftransferring power. In various embodiments, the hydraulic fluid may begenerally incompressible at the working temperatures and pressures ofthe dilatometer system. Examples of such hydraulic fluids include,without limitation, petroleum-based fluids or ionic fluids, for exampleimidazolium-based ionic liquids.

FIG. 1 illustrates an example embodiment of a pressurizable volumetricdilatometer system 1. One element of this embodiment of the dilatometersystem 1 is that the dilatometer system 1 has a larger range of volumechange than a conventional system that has its volume change restrictedby the range of its bellows. This dilatometer system 1 is apressurizable, thermally controlled dilatometer that measures volumechange in materials, due to physical, thermal or chemical processes. Inan exemplary embodiment of FIG. 1 the dilatometer system 1 may beoperated at a high pressure (in the range of 20 Ksi) and a hightemperature (up to approximately 1000 degrees Celsius) to measure volumechange in material samples. However, other embodiments may operate atany other desired pressures and temperatures, limited in part by thethermal capability of the fluid utilized in the system and theadditional system components. The pressures and/or temperatures providedherein are representative in nature and shall not be seen as limiting inany way. In this example, the dilatometer system 1 may heat a polymersample material up to the range of approximately 300 degrees Celsius andthen the polymer sample material's glass transition temperature, T_(g),is determined by measuring changes in volume at temperature andpressure. The dilatometer system 1 includes a reactor 3, a working fluid5, within the reactor 3 and within a working fluid line 7, a pump 9, ahydraulic line 11, and a hydraulic fluid 13. In a representativeembodiment, the working fluid 5 and the hydraulic fluid 13 are animmiscible fluid combination and the final intersection 21 (after beingpressurized as discussed below) of the working fluid 5 and the hydraulicfluid 13 is illustrated as labeled in FIG. 1. In general, a density trap15 is formed in the proximity of where the working fluid line 7 and thehydraulic line 11 intersect, as illustrated. Even though a P-typedensity trap is illustrated, those of ordinary skill in the art willappreciate that other types of density traps may be used to measurechanges in volume of the fluids as further discussed below. In someconfigurations, the pump 9 may be a programmable high pressure syringetype of pump, but in other embodiments it may be another suitable pump,as determined and/or understood by those of ordinary skill in the art.Suitable pumps may be capable of exerting high pressure with the abilityto meter fluid with high precision. In one example, one family ofsuitable pump for this purpose is the Teledyne Isco Model 30D syringepumps.

In this exemplary embodiment, the primary components of the dilatometersystem 1 such as the reactor 3, the working fluid line 7, the hydraulicline 11, and the pump 9 are made primarily out of rigid materials suchas a suitable metal to minimize changes of volume of components of thedilatometer system. In a representative embodiment, stainless steel isused to form many of the components of the dilatometer system asstainless steel has high stiffness and strength, and is minimallyreactive with the working fluid 5 or the hydraulic fluid 13. In oneembodiment, the reactor or sample cell is sized large enough toaccommodate the sample as well as the volume change (increase) that maycome from thermal expansion and/or phase transformation. By way ofexample only, a material specimen that the dilatometer system 1evaluates may be in the size range of 1 to 2 cubic centimeters. Thevolume of the sample cell may be approximately twice the sample volume.Other samples may include carbon fiber composites, wood samples, andvirtually any other materials deemed usable in the system.

Having introduced the basic components of the example configuration ofthe dilatometer system 1 of FIG. 1, the concept of glass transitiontemperature, T_(g), and other related concepts are explained before thefunctionality of the dilatometer system 1 is explained. Polymers aregenerally divided into two classes, thermosets and thermoplastics.Thermoset polymers are formed from resins that are initially in aviscous state. Heating the thermosetting resin cross-links the resin andincreases the strength of the polymer. In general, thermoset polymers donot substantially soften upon subsequent application of heat, andtherefore thermoset polymers can generally not be re-molded or re-heatedafter their initial forming and heating. Thermoplastic polymers may beheated, and the polymer becomes more fluid as heat is introduced. Whenthe thermoplastic polymer is maintained at a temperature below its glasstransition temperature, T_(g), the material behaves as a rigid material.As the temperature of the thermoplastic polymer exceeds the T_(g), thepolymer becomes more pliable and fluid-like and loses strength. Forcesapplied to the thermoplastic polymer below the T_(g) may result inelastic (recoverable) deformation, while the same forces applied attemperatures above the T_(g), may result in plastic (non-recoverable)deformation the thermoplastic polymer. Thermoplastic polymers aregenerally used in products and applications in which the temperature ofthe thermoplastic polymer is below the material's T_(g). Accordingly,accurate measurement of the T_(g) of thermoplastic polymers is desirablefor proper selection of materials for a product and its applications.

As illustrated in FIG. 2, when an amorphous material (line (2)) isheated from the glassy state, below the T_(g), to the rubbery state,above the T_(g), there is not an abrupt change in volume. Instead, at oraround the glass transition temperature, T_(g), of the material, thereis a change in coefficient of thermal expansion. As depicted in FIG. 2,as the material is brought through and above the T_(g), the slope of thecurve of specific volume vs. temperature, moves from a relatively lowvalue in the glassy state to a relatively higher value in the rubberystate. The intersection of the two linear line segments of the amorphousmaterial curve (2) defines the dilatometric T_(g). A comparison betweena crystalline material (1) and an amorphous material (2) is illustratedin FIG. 2. In some configurations, the dilatometer system 1 may be usedto identify the freezing temperature, T_(f), of a crystalline material.The freezing temperature, T_(f), is similar to the glass transitiontemperature, T_(g), of amorphous materials discussed above, as T_(f) isthe temperature at which a crystalline material moves from a crystallinestate to an amorphous state, as illustrated by curve (1) in FIG. 2.

In some embodiments, the change in the coefficient of thermal expansion(e.g., the slope change of specific volume vs. temperature) may bemeasured by evaluating the movement of the immiscible fluid boundarywhile steadily increasing temperature on the test sample 17 indicatesthe value of the glass transition temperature, T_(g), of the testsample.

It is important to note that while the T_(g) is an parameter that can bedetermined with a dilatometer, it is not the only parameter that may bedetermined. The various configurations of a dilatometer disclosed hereinmay be capable of measuring volume at different temperatures andpressures. As understood by those of ordinary skill in this art, thebulk modulus of a material, compressibility, specific volume,coefficient of thermal expansion, and other properties may also bedetermined using various configurations of the dilatometers disclosedherein.

In operation and with continued reference to FIG. 1, a sample 17 isplaced inside the reactor 3 as illustrated. Next, the reactor 3, theworking fluid line 7, and at least a portion of the density trap 15 willbe filled with a working fluid 5. In some embodiments, the working fluidmay be any metal or metal alloy that is fully liquid at the workingtemperatures (i.e., the liquidus temperature of the metal or metal alloyis below the lowest working temperature) of the dilatometer system 1.The second fluid is a fluid that is immiscible with the working fluid.For example, the first fluid may liquid Galinstan®, which is acommercially available gallium eutectic alloy available from GerathermMedical AG. In one example, the second fluid may be a hydraulic fluid.The working fluid 5 and the hydraulic fluid 9 form a system of at leasttwo immiscible liquids. In some embodiments, at least one of the atleast two immiscible fluids is an ionic liquid that is prone tooxidation and not miscible in many nonpolar polymers. At the same timeor at a close time during the sample testing operation, a hydraulicfluid 13 is pumped by the pump 9 into the hydraulic line 11 andpartially into the density trap 15, as illustrated in FIG. 1. Becausethe pump 9, the hydraulic line 11 the density trap 15, and the reactor 3are in fluid communication with one another, pressure may equilibrateacross the first fluid and the second fluid. However, because thehydraulic fluid 9 and working fluid 5 form a pair of immiscible fluids,they will not mix together and, instead, will form a boundary at theimmiscible fluids interface. For example, an immiscible fluid boundarymay be formed at point 19 in the density trap 15 (after pressure isadded but before heat is added to the system 1), as illustrated in FIG.1.

Liquid Galinstan, however, typically exhibits low surface tension. Thislow surface tension corresponds to an increased likelihood that theliquid Galinstan will wet solid surfaces that the liquid Galinstan comesinto contact with. Wetting certain surfaces, for example, seals andcomponents of a pump, is undesirable, and may compromise thefunctionality of certain devices. In contrast, hydraulic fluid may notbe inert with the polymeric material being sampled, in particular atelevated temperatures. Accordingly, the dilatometer system 1 of thepresent disclosure incorporates a combination of immiscible fluids: thefirst liquid is compatible with the polymeric sample being tested andthe second liquid is compatible with those components that direct theflow of fluid to encapsulate and pressurize the first liquid, whichsurrounds the sample. The boundary between the two immiscible fluids,therefore, becomes an appropriate position to monitor the change involume of the polymeric sample.

Before a test begins, pump 9 will pump hydraulic fluid 9 into thehydraulic line 11 to pressurize the dilatometer system 1 includingreactor 3 to a desired pressure. This may cause the hydraulicfluid/working fluid boundary to be located at position 19 (FIG. 1) ondensity trap 15 (again after pressure but before heat is added to thesystem 1). Once the desired pressure is established by reading apressure gauge or having a computer detect the desired pressure with asensor, the temperature of the reactor 3 and the sample 17 inside thereactor 3 is increased in order to determine the glass transitiontemperature, T_(g). As illustrated in FIG. 2, the specific volume of apolymeric sample 17 will increase as the temperature of the workingfluid 5 increases, thereby allowing more working fluid 5 to be pushedinto the density trap 15. For example, the boundary of the immisciblefluids (hydraulic fluid 13 and working fluid 5) may move from point 19(FIG. 1) to point 21 in the density trap 15. The glass transitiontemperature, T_(g), is determined when the rate of increase of specificvolume increases to a higher slope/rate of increase as the sample entersthe rubbery state as indicated by point 20 in FIG. 2. For example, thehydraulic fluid 13 may reach position 21 on the hydraulic line/densitytrap 15 as illustrated in FIG. 1 as the sample approaches and enters theliquid state. The glass transition temperature, T_(g), may be calculatedbased on the position of the immiscible fluid boundary based on thetemperature, as depicted in FIG. 2.

It should be noted that pressure of the fluids and heat may affect(expand) the reactor 3, the pump 9, the working fluid line 7, hydraulicline 11, the density trap 15, as well as other components of thedilatometer system 1 that may result in an increased system volumechange being recorded. Under ideal test conditions, nothing except thetest sample may contract or expand. Thus, the change in volume measuredduring the test, including thermal expansion, will be the result of thecompression/expansion of the pressurizing fluid 13, the working fluid 5,the equipment stiffness and the specimen 17. The dilatometer system 1may be designed and sized with a factor of safety, which shouldsignificantly minimize the elastic contribution from pressurization.Because the combination of fluids (the working fluid 5 and the hydraulicfluid 13) are immiscible, the contribution to the overall volume changewill be repeatable and additive. The fluid volume change frompressurization will be the compressibility of the working fluid timesthe volume of the working fluid plus the compressibility of thepressurizing fluid times the volume of the pressurizing fluid. Further,the volume change of the fluid and the surrounding enclosure caused bytemperature and pressure variation may be captured and the data gatheredmay be calibrated to minimize the introduction of error into thecompilation of data. As understood by those of ordinary skill in theart, this can be computed or measured to create a calibration curve forthe dilatometer system 1 that can be subtracted from the observed totalvolumetric changes during the test, resulting in the net volume changedue to the specimen 17 to accurately record the specimen's volumechange.

In some instances it may be desired to determine T_(g) for a variety ofdifferent pressures. In certain cases, the pump 9 will increase pressureon the hydraulic fluid 13 to a first higher pressure which will in turnincrease pressure on the working fluid 5 and the test sample 17. Higherpressure requires more heat to reach the T_(g). As discussed later withreference to FIG. 3, the heat may be supplied by a heater associatedwith the reactor 3. Once the new T_(g) is found at the first higherpressure, the dilatometer system 1 may first be cooled and then the pump9 may again increase the pressure on the hydraulic fluid 13, which againincreases pressure on the working fluid 5 and the test sample 17 to asecond higher pressure. Next, the temperature of the reactor 3 is againincreased/swept higher until a new higher T_(g) is found at the newsecond higher pressure and temperature combination. This can be repeatedto find pressure/temperature combinations for as many different T_(g)values of a sample or material as desired. Similarly, in somecircumstances, it may be desirable to decrease pressure. For example, tomeasure the bulk modulus of a material the temperature may be heldconstant while pressure and volume change are measured both duringloading (increase in pressure) and unloading (decrease in pressure).Comparing these curves would be indicative of sample densification.Also, an operator desiring to run a test maintaining volume constantwhile changing temperature, would appreciate that the pressure may haveto either increase or decrease to maintain the constant volume(isochoric). In general, a user may want to study a sample underisothermal, isobaric, or isochoric conditions.

The dilatometer system 1 may measure many thermodynamic properties inmaterials. These include T_(g) (if single phase), 2 T_(g)s (if twophase), crystal melting and cooling temperatures (along with volumechange associated with melting or solidification) that would beindicative of a degree of crystallinity. The dilatometer system 1 mayalso be used to evaluate engineering properties like bulk modulus, whichmay allow for back-calculating other elastic properties of anisotropicmaterials, such as films and fibers. The dilatometer system 1 may alsoused to determine thermoplastic properties of some materials.

In further detail, in some conditions, the determination of T_(g) forpolymers has been found to be rate dependent. Thus, FIG. 3 illustrates apressurizable dilatometer system 100 that utilizes an electroniccomputer (e.g., processor 151) that is used to control the pump 9 andmay be used to add a level of reproducibility that was not previouslyavailable in prior art systems, in particular to rate-sensitive materialproperties. The processor 151 or another microprocessor basedcontroller/logic may also be added to control a heater 149 that isassociated with the reactor 3 to provide for controllable heating andcooling rates. In some embodiments, the processor 151 may interfacethrough a pump controller 153 and a heater controller 155 whencontrolling the pump 9 and heater 149.

“Processor” and “Logic”, as used herein, includes but is not limited tohardware, firmware, software and/or combinations of each to perform afunction(s) or an action(s), and/or to cause a function or action fromanother logic, method, and/or system. For example, based on a desiredapplication or needs, logic and/or processor may include asoftware-controlled microprocessor, discrete logic, an applicationspecific integrated circuit (ASIC), a programmed logic device, a memorydevice containing instructions or the like. Logic and/or processor mayinclude one or more gates, combinations of gates, or other circuitcomponents. Logic and/or a processor may also be fully embodied assoftware. In various embodiments, the processor may execute the logicthat is stored as a computer readable instruction set that is stored inthe memory that is associated with the processor. Where multiple logicsand/or processors are described, it may be possible to incorporate themultiple logics and/or processors into one physical logic (orprocessors). Similarly, where a single logic and/or processor isdescribed, it may be possible to distribute that single logic and/orprocessor between multiple physical logics and/or processors.

The dilatometer system 100 of FIG. 3 further includes a working fluidtank 123 and an argon tank 141 or a tank with another non-reactive gas.In one configuration, the working fluid 5 is Galinstan, which is acommercially available gallium eutectic. As illustrated, three-portvalves 131, 137 connect the working fluid tank 123 and the argon (oranother suitable non-reactive gas) tank 141 to the reactor 3. Two-portvalves 133, 135 provide a way to connect the reactor 3 and the workingfluid tank 23 to atmosphere (ATM). Two-port valves 139 and 141 provide away to shut off the hydraulic line 11 from the density trap 15 as wellas a way to shut off the pump 9 from a hydraulic fluid tank 143. Thepump 9 contains a pressure gauge or another suitable pressuremeasurement device 125 to indicate a pressure in the pump 9 and thedilatometer system 100. The dilatometer system 100 of FIG. 3 has manysimilar components of the system 1 of FIG. 1. Similar components includea reactor, 3, a working fluid 5, within the reactor 3 and within aworking fluid line 7, a pump 9, a hydraulic line 11, and a hydraulicfluid 13. An end of the working fluid line 7 and the hydraulic line 11form a density trap 15 in the form of a P-trap, as illustrated. Ofcourse, in other embodiments, other types of density traps may be used.

In preparation for a test, the valve 131 connected to the argon tank 141can be opened to allow argon to push working fluid 5 from the workingfluid tank 123 into the reactor 3 as well as the working fluid line 7and to the density trap 15. Valve 135 is opened to allow air or othergasses in the reactor 3 to vent to the atmosphere when the working fluid5 is being filled into the reactor 3. Valve 141 and valve 139 are bothopened to allow hydraulic fluid 13 to flow into the pump 9 as well asthrough the hydraulic line to the density trap 15 and valve 141 isclosed when the pump 9 and hydraulic fluid line 11 are filled. After thedilatometer system 100 is filled with a working fluid and hydraulicfluid, valves 141, 131, and 135 are closed. Three-port valve 137 isclosed with respect to the working fluid tank 123 but still allowsworking fluid 5 to flow between the density trap 15 and the reactor 3.

In operation with the test sample/specimen 17 in place, the processor151 may interface through a pump controller 153 connected to the pump 9and a heater controller 155 connected to the heater 149. For example, inan isobaric test the processor 151 will control the pump 9 to create aprecise desired pressure within the dilatometer system 100 and then theprocessor 151 will cause the heater controller 155 to systematicallyincrease/sweep the temperature upward looking for the glass transitiontemperature, T_(g), for example. In same configurations, the heater 149may contain resistive heating elements or inductive heating elementsthat introduce heat to the reactor 3. Additional embodiments may includeheaters that introduce heat to the reactor 3 in other ways as understoodby those of ordinary skill in the art.

Using the processor 151, the dilatometer system 100 of FIG. 3 maymeasure the specific volume and temperature and provide this data inreal time. This configuration of a dilatometer system 100 may runisothermal tests, where a temperature is reached at a proscribed heatingrate before conducting a pressurization cycle. As mentioned above, thedilatometer system 100 may also be able run isobaric tests to reach aproscribed pressure and then run a thermal cycle. As understood by thoseof ordinary skill in the art, the system 100 may determine otherproperties of materials because the system 100 has the ability to runisochoric tests at a constant volume, in which the system 100 heats andpressurizes the test sample 17 in a controlled manner such that thevolume of the specimen 17 remains constant. As understood by those ofordinary skill in the art, isochoric test may be useful to find otherengineering properties of materials.

In summary, the dilatometer system 1 of FIG. 1 and dilatometer system100 of FIG. 3 greatly simplifies the operation of prior art dilatometersis the use of two or more immiscible fluids and a density trap 15. Twofluids are useful to conduct the test because the working fluid 5 in thereactor 3, is substantially inert to test sample 17 and may have thermalcapability to, for example, at least about 200 degrees Celsius higherthan the predicted T_(g) of sample 17. In other embodiments, the thermalcapability of the dilatometer system 1 may be at least about 1000degrees Celsius. The pressurizing (hydraulic) fluid 13 should becompatible with the pump seals and surfaces. The two fluids are keptphysically separated, except for the moving interface formed by theimmiscible fluids. Each of the fluids are maintained away from areasthat would detract from the operation of the dilatometer system 100. Ifthe pair of immiscible fluids are any suitable hydraulic fluid andGalinstan, a commercially available gallium eutectic, the hydraulicfluid 13 may be kept out of the heating zone and not contact the polymersample 17. The working fluid 5 should be kept out of the pump 9 forreasons of corrosion and pump durability. The immiscibility of thefluids, and the small interfacial area, keeps the fluids from mixing orcombining and the density trap 15 keeps the lighter fluid from“climbing” over the heavier fluid and getting into the reactor 3. Theimmiscibility of the liquids allow this to be done without thecomplication of a prior art type of bellows system used to separate andsegregate the liquids. The immiscibility of the liquids reduces overallsystem stiffness and increases the responsiveness of the dilatometersystem 100. Further, the dilatometer system according to the presentdisclosure may provide more repeatable results with enhanced accuracy ascompared to conventional dilatometers. Ideally, the working fluidsurrounds the test sample 17 in the chamber when it is being tested.Samples that may be tested are polymers and other materials in whichchanges in volume under one or more pressures and/or temperatures aredesired to be known.

Example methods may be better appreciated with reference to flowdiagrams. For purposes of simplicity, explanation of the illustratedmethodologies are shown and described as a series of blocks. It is to beappreciated that the methodologies are not limited by the order of theblocks, as some blocks can occur in different orders and/or concurrentlywith other blocks from that shown and described. Moreover, less than allthe illustrated blocks may be required to implement an examplemethodology. Blocks may be combined or separated into multiplecomponents. Furthermore, additional and/or alternative methodologies canemploy additional, not illustrated blocks.

FIG. 4 illustrates a method 400 of using two different immiscible fluidsin a dilatometer. The method 400 begins by filling a reactor containinga test sample as well as filling a first fluid line leading at leastpartially into a density trap with a first fluid, at 402. A second fluidis pumped through a second fluid line and at least partially into thedensity trap, at 404, so that the first fluid and the second fluidcontact each other in the density trap and form and immiscible fluidboundary/interface because the first and second fluid pairs areimmiscible fluid pairs. A desired pressure is applied to the secondfluid, at 406, to pressurize the second fluid, the first fluid, and thetest sample. The reactor and test sample are heated, at 408, through arange of temperatures. The glass transition temperature is found, at410, based, at least in part, on the movement of the immiscible fluidinterface in the density trap. In some configurations, the rate ofmovement of the immiscible fluid interface changes, indicating a rate ofchange of a specific volume of the test sample, which indicates at whattemperature the glass transition temperature, T_(g), occurs. In otherconfigurations, the first fluid is Galinstan and the second fluid is ahydraulic fluid.

FIG. 5 illustrates an example computing device in which at least someportions of example systems and methods described herein, andequivalents, may operate. The example computing device may be a computer500 that includes a processor 502, a memory 504, and input/output ports510 operably connected on a bus 508. In one example, the computer 500may include a pressure and temperature control logic 530 configured tocontrol a pump to pressure a pair of immiscible fluids in a dilatometeras described above and to control the heater associated with a reactor.In some configurations the computer 500 may be able to calculate variousparameters of a test sample in a reactor of the dilatometer based, atleast in part, on volume changes as indicated by an intersection of aboundary of the two immiscible fluids. In different examples, thepressure and temperature control logic 530 may be implemented inhardware, software, firmware, and/or combinations thereof. Thus, logic530 may provide means (e.g., hardware, software, firmware) forcontrolling a dilatometer system with a pair of two immiscible fluidsand provide a means of finding one or more parameters of a test sampleunder test in the dilatometer system. While logic 530 is illustrated asa hardware component attached to bus 508, it is to be appreciated thatin one example, logic 530 could be implemented in processor 502.

Generally describing an example configuration of computer 500, processor502 may be a variety of various processors including dual microprocessorand other multi-processor architectures. Memory 504 may include volatilememory and/or non-volatile memory. Non-volatile memory may include, forexample, ROM, PROM, EPROM, and EEPROM, Volatile memory may include, forexample, RAM, synchronous RAM (SRAM), dynamic RAM (DRAM), synchronousDRAM (SDRAM), double data rate SDRAM (DDR SDRAM), direct RAM bus RAM(DRRAM) and the like.

A disk 506 may be operably connected to computer 500 via, for example,an input/output interface (e.g., card, device) 518 and an input/outputport 510. Disk 506 may be, for example, a magnetic disk drive, a solidstate disk drive, a floppy disk drive, a tape drive, a Zip drive, aflash memory card, and/or a memory stick. Furthermore, disk 506 may be aCD-ROM, a CD recordable drive (CD-R drive), a CD rewriteable drive(CD-RW drive), and/or a digital video ROM drive (DVD ROM). Memory 504can store a process 514 and/or a data 516, for example. Disk 506 and/ormemory 504 can store an operating system that controls and allocatesresources of computer 500.

Bus 508 may be a single internal bus interconnect architecture and/orother bus or mesh architectures. While a single bus is illustrated, itis to be appreciated that computer 500 may communicate with variousdevices, logics, and peripherals using other busses (e.g., PCIE, SATA,Infiniband, 1384, USB, Ethernet). Bus 508 can be types including, forexample, a memory bus, a memory controller, a peripheral bus, anexternal bus, a crossbar switch, and/or a local bus.

Computer 500 may interact with input/output devices via input/outputinterfaces 518 and input/output ports 510. Input/output devices may be,for example, a keyboard, a microphone, a pointing and selection device,cameras, video cards, displays, the disk 506, the network devices 520,and so on. The input/output ports 510 may include, for example, serialports, parallel ports, USB ports and the like.

The computer 500 can operate in a network environment and thus may beconnected to network devices 520 via input/output interfaces 518, and/orthe input/output ports 510. Through network devices 520, computer 500may interact with a network. Through the network, computer 500 may belogically connected to remote computers. Networks with which computer500 may interact include, but are not limited to, a local area network(LAN), a wide area network (WAN), and other networks. The networks maybe wired and/or wireless networks.

In the foregoing description, certain terms have been used for brevity,clearness, and understanding. No unnecessary limitations are to beimplied therefrom beyond the requirement of the prior art because suchterms are used for descriptive purposes and are intended to be broadlyconstrued. Therefore, the disclosure is not limited to the specificdetails, the representative embodiments, and illustrative examples shownand described. Thus, this application is intended to embracealterations, modifications, and variations that fall within the scope ofthe appended claims.

Moreover, the description and illustration of embodiments according tothe disclosure are examples and the disclosure is not limited to theexact details shown or described. References to “the preferredembodiment”, “an embodiment”, “one example”, “an example” and so on,indicate that the embodiment(s) or example(s) so described may include aparticular feature, structure, characteristic, property, element, orlimitation, but that not every embodiment or example necessarilyincludes that particular feature, structure, characteristic, property,element, or limitation.

What is claimed is:
 1. A dilatometer system for measuring acharacteristic of a test sample, comprising: a reactor adapted toreceive the test sample; a density trap in fluid communication with thereactor; a first fluid selectively filling the reactor and a portion ofthe density trap; a second fluid selectively filling a portion of thedensity trap; and a heater that selectively heats the first fluid,wherein the first fluid and the second fluid are immiscible with oneanother and selectively form an immiscible fluid boundary in the densitytrap.
 2. The dilatometer system of claim 1, further comprising a pump influid communication with the density trap.
 3. The dilatometer system ofclaim 2, wherein the second fluid is positioned to prime the pump. 4.The dilatometer system of claim 2, wherein the pump selectivelypressurizes the second fluid directly, wherein the second fluidpressurizes the first fluid and the test sample.
 5. The dilatometersystem of claim 1, wherein a position of the immiscible fluid boundarywithin the density trap changes in position based on the characteristicof the test sample.
 6. The dilatometer system of claim 1, where theheater is adapted to heat at least the first fluid in the reactor andthe test sample over a range of temperatures.
 7. The dilatometer systemof claim 6, wherein a rate change in the movement of the immisciblefluid boundary over the range of temperatures indicates the glasstransition temperature, T_(g), of the test sample.
 8. The dilatometersystem of claim 6 further comprising a computer comprising a processorand a memory and having a computer readable instruction set stored inthe memory that, when executed by the processor: the computer instructsthe heater to heat at least the first fluid and the test sample over therange of temperatures; and the computer monitors the position of theimmiscible fluid boundary over the range of temperatures.
 9. Thedilatometer system of claim 8, wherein, when the computer readableinstruction set is executed by the processor, the computer calculatesthe glass transition temperature, T_(g), of the test sample.
 10. Thedilatometer system of claim 6, wherein: the first fluid is a metal ormetal alloy that is full liquid over the range of temperatures; and thesecond fluid is a hydraulic fluid.
 11. The dilatometer system of claim10, wherein the first fluid is Galinstan.
 12. The dilatometer system ofclaim 2, further comprising: a working fluid tank in fluid communicationwith the reactor and adapted to selectively store at least some of thefirst liquid; and a hydraulic fluid tank in fluid communication with thepump and adapted to store at least some of the second liquid.
 13. Thedilatometer system of claim 12, further comprising: a first 2-port valvein fluid communication between the hydraulic fluid tank and the pump; asecond 2-port valve in fluid communication between the pump and a secondfluid line; a first 3-port value in fluid communication between theworking fluid tank, and a portion of a first fluid line connected to thereactor, and another portion of the first fluid line connected to thedensity trap; and a third 2-port valve in fluid communication betweenthe working fluid tank and local atmosphere.
 14. The dilatometer systemof claim 13, further comprising: a computer adapted to control the first2-port valve, the second 2-port valve when priming the pump, the secondfluid line, and the density trap with the second fluid when initializingthe dilatometer system; wherein the computer is adapted to control thefirst 3-port valve, and the third 2-port valve when filling the firstfluid into the first fluid line, the density trap, and the reactor wheninitializing the dilatometer system; wherein the computer is adapted tocontrol the first 2-port valve, the second 2-port valve when removingthe second fluid from the pump, the second fluid line, and the densitytrap when shutting down the dilatometer system; and wherein the computeris adapted to control the first 3-port valve, and the third 2-port valvewhen removing the first fluid from the first fluid line, the densitytrap, and the reactor when shutting down the dilatometer system.
 15. Thedilatometer system of claim 14, further comprising: an argon tankconnected between the working fluid tank and the reactor with a second3-port valve, wherein the computer is adapted to control the second3-port valve so that argon in the argon tank will assist in filling thefirst fluid into the first fluid line, the density trap, and the reactorwhen initializing the dilatometer system, and wherein the computer isadapted to control the second 3-port valve so that argon in the argontank will assist in removing the first fluid from the first fluid line,the density trap, and the reactor when shutting down the dilatometersystem.
 16. The dilatometer system of claim 2, wherein the pump is asyringe pump.
 17. The dilatometer system of claim 1, wherein the densitytrap is a P-type of trap.
 18. The dilatometer system of claim 2, furthercomprising: a pressure measurement device for sensing the pressure ofthe fluid exiting the pump; a pressure measurement device for sensingthe pressure of the first fluid inside the reactor; and a temperaturemeasurement device for sensing the temperature of the first fluid insidethe reactor.
 19. A dilatometer system for measuring a characteristic ofa test sample, comprising: a reactor adapted to receive the test sample;a first fluid selectively filling the reactor; a second fluid that isimmiscible with the first fluid, the second fluid forming an immisciblefluid boundary at a location where the first fluid contacts the secondfluid; a heater that selectively heats the first fluid; and a computercomprising a processor and a memory and having a computer readableinstruction set stored in the memory that, when executed by theprocessor: the computer instructs the heater to heat at least the firstfluid and the test sample over a range of temperatures; and the computermonitors a volume of the first fluid based on the position of theimmiscible fluid boundary over the range of temperatures.
 20. Thedilatometer system of claim 19, wherein, when the computer readableinstruction set is executed by the processor, the computer calculatesthe glass transition temperature, T_(g), of the test sample.